Do you mean actual control with counters, because that deck is virtually dead thanks to all the super friends decks (primarily thanks to little Teferi making counterspells useless). If you mean the Super Friends version it's actually midrange. It's probably the most well rounded deck but it does lose badly to the Green Ramp decks that play with Nissa.
And when you say Arena, are you playing Bo1 or Bo3? That also severely impacts what you should play.
And when you say Arena, are you playing Bo1 or Bo3? That also severely impacts what you should play.
Standard: BG Golgari Midrange
Modern: U Merfolk GWUBR 5 Color Humans UBW Esper Gifts GW Bogles